The present invention relates to a hoist system, comprising at least one mast, a hoist trolley moveable externally along the mast, and a platform, which is articulately coupled to the hoist trolley so that it is horizontally pivoting about a substantially vertical axis between two end positions relative to the hoist trolley. The vertical axis is situated between the hoist trolley and the platform, as seen horizontally.
When renovating or constructing buildings, a hoist system of this kind provides transport of personnel and materials to and from the various landings of the building. The hoist system may also be utilised for work on the facade of the building by allowing building workers to stand on the platform when working. To make the entire facade of the building accessible from the platforms often a great number of masts with intermediate mediate platforms has to be placed in a row along the facade of the building, since for strength and security reasons each platform has a limited length. The hoist system may also be utilised in permanent installations for the maintenance of larger machines.
One type of platform typically used for work on building facades comprises smaller sections which can be interconnected to form an assembled rectangular platform with a suitable length. The assembled platform is coupled with its two short ends to two hoist trolleys running along two adjacent masts between which the platform extends.
In a known hoist system several masts can be arranged in a straight row along a straight building facade with platforms coupled between hoist trolleys of adjacent masts. This results in the advantage that the number of masts required along the building facade are minimised, since each mast, except the first and last mast in said row of masts, is utilised for carrying two platforms at mutual sides of the mast. In the known hoist system it is also possible to form a right-angled mast arrangement, in which the last mast in a straight mast row constitute the first mast in another mast row running perpendicular from the first mentioned mast row, i.e. said first and last mast constitute a mast common to both mast rows. Thus, the mast rows form one single continuous row of masts interconnected by the platforms.
In the known hoist system described above the common mast may have only one hoist trolley, which is coupled to a platform extending along the first mentioned mast row and to another platform extending along the last mentioned mast row. Alternatively the common mast may have two hoist trolleys, one of which is coupled to the platform which extends along the first mentioned mast row and the other hoist trolley of which is coupled to a platform extending along the last mentioned mast row. The described right-angled mast arrangement is suited for such ordinary facade sections which extend perpendicularly to each other and end in a corner. The common mast of course is placed at such a corner.
However, there are buildings with facade sections that form non-right-angled corners between adjacent facade sections, usually obtuse-angled corners, i.e. having angles between 90 and 180xc2x0. In contrast to the case described above with only one mast at each right-angled corner, in a building of this kind two masts, one in each mast row, must be placed closed to each other at the non-right-angled corner to be coupled to two adjacent platforms extending along respective facade sections.
The reason for this is that known hoist systems currently available on the market do not admit that one platform is carried by two adjacent masts which are turned relative to each other with an angle corresponding to the obtuse angle between adjacent facade sections. If the building has many such non-right-angled corners the costs for installation of twin masts at the corners may be significant, in particular when considering that each mast has to be equipped with a hoist trolley and a drive unit for driving the latter along the mast.
An object of the present invention is to provide a hoist system that allows installation of one single mast at a non-right-angled corner of for instance a building or a larger machine and installation of platforms extending from one or two hoist trolleys on the mast substantially in parallel with the facade sections forming the non-right-angled corner.
Another object of the invention is to provide a versatile hoist system allowing installation of a continuous row of masts and platforms along a facade including facade sections forming non-right-angled as well as right-angled corners.
These objects are achieved by means of a hoist system of the kind stated initially, which is characterised in that the position of the vertical axis is adjustable for adjusting the distance between the hoist trolley and the platform. Hereby the mast may be placed at a non-right-angled corner of a building and be anchored in a traditional manner at one of the two facade sections extending from the non-right-angled corner, and the platform can be angled horizontally relative to the hoist trolley so that it extends substantially in parallel with the second facade section.
Advantageously, the platform is pivoting 180xc2x0 between the end positions, in such a manner that when the platform is at any of the end positions it can extend in parallel with a facade section extending from a right-angled corner of a building or a larger machine. In other words the platform may extend in a traditional manner out from the hoist trolley when it is adjusted in a central position, half way between the end positions, for enabling installation at a right-angled corner as well.
Furthermore, the advantage is achieved that the distance between the hoist trolley and the platform can be minimised when the platform is in said central position, which facilitates for a building worker on the platform to work on a building facade close to a mast. When the platform is to be turned from the central position to a position between the central position and any of the end positions, in accordance with the invention the position of the vertical axis first is adjusted so that the distance between the hoist trolley and the platform is increased. The required increase in distance depends on how broad the platform is.
The vertical axis is preferably adjustable at different distances from the hoist trolley and/or at different distances from the platform, as seen horizontally.
According to a preferred embodiment of the invention, the hoist system comprises a first coupling element coupled to the hoist trolley, and a second coupling element coupled to the platform, the second coupling element being articulately coupled to the first coupling element so that it is pivoting about said vertical axis.
To enable coupling of the platform to another hoist trolley on an adjacent mast by means of a further coupling element of the same kind as said first and second coupling elements, the platform is suitably articulately coupled to the second coupling element so that the platform is pivoting about a substantially horizontal axis. Since the hoist trolleys on two adjacent masts normally cannot be moved exactly synchronously with each other along the masts, the horizontal axis between the platform and the second coupling element at the respective masts allows that the platform can be tilted somewhat relative to the horizontal plane during hoisting or lowering, so that damaging stresses in the hoist system are avoided.
Preferably the first coupling element is articulately coupled to the hoist trolley so that it is pivoting about a further substantially horizontal axis, which further reduces the risk of damaging stresses arising in the hoist system, when a platform is moved along two adjacent masts.
The first coupling element may have at least two vertical bores situated at different distances from the hoist trolley, while the second coupling element may have at least one vertical bore spaced from the platform. Furthermore, an axle pin may releasably extend from any of the bores of the first coupling element and through the bore of the second coupling element, whereby the axle pin is coaxial with said vertical axis. Suitably, the bores of the first coupling element form a row of bores extending centrally out of the hoist trolley.